PART III: APPLICATIONS 

 Ash Wednesday Storm 



84. As a verification test of the numerical modeling system's ability to 

 determine sediment transport near Oregon Inlet for an extreme storm event, the 

 Ash Wednesday storm of 1962 was simulated. The storm lasted from 7 to 



11 March 1962. This record northeaster caused severe beach erosion along 

 Bodie Island and Pea Island on the north and south sides of the inlet, respec- 

 tively. The erosion continued until it reached high dunes. On the northern 

 part of Bodie Island, the land was low and flooded. 



85. To run the simulation, the wave climate (significant wave height, 

 period, and direction) in deep water was hindcast at 3-hr intervals throughout 

 the storm using WESWIS. Simultaneously, the tidal and storm surge levels and 

 currents during the storm were obtained using the numerical tide and surge 

 model . 



86. Since the major part of the net sediment transport during a severe 

 storm is in the onshore-offshore direction, only the profile response model 

 was run using the information on waves, astronomical tides, and storm surge 

 levels. The measured shore-normal pre-storm profiles for the two islands were 

 furnished by the National Park Service (NPS) , US Department of the Interior 

 (DOI), and were taken a year prior to the storm. The poststorm profiles were 

 taken a few weeks after the storm and were furnished by the NPS. Thus the 

 measured data do not represent just the erosion due to the storm. However, 

 the erosion produced by the storm was much greater than normal yearly fluctua- 

 tions. The measured profiles indicate that shoreline erosion varied from 

 sixty to several hundred metres with higher erosion being near the inlet. 

 Figures 32 and 33 present a comparison between measured shore-normal erosion 

 and numerical model results. The agreement is remarkable, considering the 

 uncertainties associated with the measured data. 



Evaluation Of Nonstructural Solution 



87. As an alternative to the inlet stabilization of Oregon Inlet that 

 was authorized in the overall Manteo (Shallowbag) Bay project, DOI proposed a 

 dredging and disposal procedure that would not require the construction of 



68 



